1. Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, B-3001 Heverlee, Belgium.
2. Corresponding author. Phone: +32 (0)16321634. Fax: +32 (0)16321997. E-mail: joke.buggenhout@biw.kuleuven.be